1. Field of the Invention
This invention relates to illumination systems designed to improve image resolution and permit look-around viewing in liquid crystal and similar flat panel transmissive three dimensional (3-D) displays and enhanced resolution two dimensional (2-D) displays, for use in computers, television and the like viewing apparatus.
2. Prior Art
Several display systems are on the market today which are capable of generating three-dimensional images based on the use of stereopairs, i.e., complementary images, which when directed to the appropriate eye of the observer, produce a perception of three-dimensionality. Two of such systems, one made by Stereographics, Inc., the other by Tektronix Corp., utilize cathode ray tubes in conjunction with liquid crystal light valves designed to direct the appropriate half of the stereopair to the left or right eye of the observer. Both of these systems require the observer to wear special glasses. In addition, in order to achieve full resolution, these displays operate at frame rate twice the standard television (TV) scanning rates, thus making them incompatible with commercially available TV scanners, video camera recorders (VCR), and like apparatus.
A third system made by Dimension Technologies Inc. is autostereoscopic, i.e., it permits the observer to perceive 3-D without the need to wear glasses. The system uses a transmissive image generating liquid crystal panel (LCD) and is disclosed in U.S. Pat. Nos. 4,717,949; 4,829,365 and 5,040,878. In this system a multiplicity of parallel, equidistant, thin, bright, vertical light lines is generated using an optical device termed the "reflection plate" which carries on its one surface opposite the planar surface facing the LCD, a series of parallel ridges equal in numbers to the number of said light lines. The ridges, triangular in cross-section, are designed to intercept light rays tangentially projected by a cylindrical lens onto said ridge-bearing surface of said reflection plate from a linearly configured light source disposed on the vertical side of the LCD. This method for generating a lattice of lines is specifically described in U.S. Pat. No. 5,040,878. An image-generating LCD is situated parallel to and in front of a reflection plate, separated by a small fixed distance of, say, 3 mm, such that the observer, due to the parallax effect of vision, sees with his left eye the light lines through the odd-numbered pixel columns of the LCD, and the even-numbered pixel columns with his right eye. Thus, an illusion of depth is created, albeit by sacrificing one half of the pixel resolution in the 3-D image.
Another optical configuration for the generation of lines for an autostereoscopic display has been disclosed in U.S. Pat. No. 5,036,385, which employs a lenticular lens or fly's eye lens to generate a lattice of light lines. This configuration allows multiple sets of light lines in different locations to be made to flash on and off in sequence, allowing for the display of full resolution autostereoscopic images that can be viewed in correct perspective from across a wide angle. These configurations also allows the generation of multiple sets of light lines or points for the display of two dimensional images with resolution greater than that provided by the pixels of the LCD.
Accordingly, it is an object of this invention to provide illumination systems for imaging devices, such as disclosed in U.S. Pat. No. 5,036,385, which will be effective, economical and convenient for implementation of full resolution 3-D displays, look around 3-D displays, and enhanced resolution 2-D displays.
Another object of this invention is the use of fluorescent lamps for the illumination system.
A further object of this invention is to utilize stroboscopic gas filled arc lamps for said illumination systems.
Yet another object of this invention is to use electro-optical shutters in conjunction with the appropriate light source for said illumination systems.
Still another object of this invention is to utilize high-brightness projection type cathode ray tubes as the means for generating appropriate light patterns for use in said illumination systems.
An additional object of this invention is to use two-dimensional matrices of high-brightness light-emitting diodes (LEDs) of any one or any combination of at least three different colors as the means for generating appropriate light patterns for use in said illumination systems.
A further object of this invention is to use an electro-luminescent or AC plasma display as light sources for generating appropriate light patterns for use in said illumination systems.
Yet another object of this invention is to provide electronic control systems to control the timing of on-off states of said light sources and said electro-optical shutters in synchronization with the raster scanning of said flat panel displays for the purpose of formation of 3-D and 2-D images.
Still a further object of this invention is the implementation of said illumination systems using a plurality of light sources emitting light of different colors in conjunction with a monochromatic flat panel light valve displays for the purpose of generating full resolution 3-D and enhanced resolution 2-D color images. Still other objects will be apparent to those skilled in the art upon reference to the following detailed description and the claims.